The most remote and least visited of Cancun's outlying islands is Isla Contoy, a nature preserve where the number of visitors is strictly limited to no more than 200 per day. Typically, though, fewer than 100 people make the excursion to this haven for sea birds, turtles, and other species, some of which are endangered. More than 150 different types of birds have been spotted here and at least 98 plant species grow on the small island. Once on Isla Contoy, you can spend your afternoon enjoying the beach or you can choose to take a guided tour with a biologist to learn more about its flora and fauna. Visits include lunch.